1. Field of the Invention
The present invention relates to a current sensor which measures a magnitude of electric currents, and particularly, to a current sensor which detects currents flowing through a conductor through a electromagnetic conversion element.
2. Description of the Related Art
Recently, in the field of electric automobiles or solar cells, large output and high performance of automobiles and solar cell devices have been accomplished. The current value handled in the field has been enlarged accordingly, so a current sensor which contactlessly measures large direct currents is widely used. As such a current sensor, a sensor which includes a electromagnetic conversion element detecting currents, targets of detection, flowing through a conductor through the change of magnetic field around the conductor has been proposed. Also, as a current sensor, a current sensor having a wide measuring range has been developed.
As an example of the current sensor having a wide measuring range, there is a current sensor which can measure current values at places having a different intensity of the magnetic field caused by currents, by diposing two magnetic sensors at locations differing in distances from a conductor (Japanese Unexamined Patent Application Publication No. 2004-132790). In addition, there is a current sensor in which a portion shunting currents is provided in a conductor to minimize the magnetic field caused by the conductor so that the measuring range widens (Japanese Unexamined Patent Application Publication No. 10-73619).
However, since the current sensor in the JP-A 2004-132790 has a wide measuring range, the distance from the conductor needs to be increased, and as a result, a large space is required. Moreover, if the magnetic sensors are far away from the conductor, it is difficult to counteract differences in noise generated between the magnetic sensors. Also, the current sensor in JP-A 10-73619 has a problem in that, since the measuring range widens in response to current shunting, accuracy decreases in detecting minute electric currents.